XML serialization and deserialization

ABSTRACT

A data structure includes means for representing a programming type and means for representing an attribute. The specified attribute indicates that an instance of the programming type is to be serialized with XML.

RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 09/894,829, filedJun. 29, 2001, titled “XML SERIALIZATION AND DESERIALIZATION”, which ishereby incorporated herein by reference.

BACKGROUND

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

Simple Object Access Protocol (SOAP) is conventionally used for a firstprogram to communicate information to a second program that may berunning simultaneously on the same computer as the first program or ontwo different computers that may or may not be running the sameoperating system. In that regard, SOAP is used for encoding, orserializing, defined data structures. For example, SOAP specifiesexactly how an HTTP header and an XML file are serialized so that oneprogram can send a request to another program, passing information inthe request.

Nevertheless, what is needed is a way to serialize an object having anarbitrary structure into an XML document so that the structure and theinformation contained in the object can be communicated between twoprograms that may be running simultaneously on the same computer or maybe running on different computers that may or may not be runningdifferent operating systems.

SUMMARY

The present invention provides a way to serialize an object having anarbitrary structure into an XML document so that the structure and theinformation contained in the object can be communicated between twoprograms that may be running simultaneously on the same computer, orthat may be running on different computers that may or may not berunning different operating systems. Additionally, the present inventioncan be used by a single program to save data for later use, such asafter the computer on which the program is running has been turned offand then turned back on.

The advantages of the present invention are provided by a method forserializing an object instance to a serial format in which a mapping isgenerated between an arbitrary annotated source code file and a schema.The mapping is an internal structure used by the present invention fordefining a correspondence between the shape of an object instance andthe format of the document having the serial format. The arbitraryannotated source code contains programming types that describe the shapeof an object instance, and the schema describes the format of a documenthaving a serial format, such as XML. The mapping can be generated basedeither on an arbitrary annotated source code file or the pattern of adefined schema. After the mapping has been generated, an object instancecorresponding to the arbitrary annotated source code is converted to theserial format based on the mapping by converting public properties,public fields and method parameters of the object instance to a documenthaving the serial format. The serial format contains a shape of eachclass of the object instance and contains data contained within theobject instance. According to the invention, the object instance ispreferably converted to an XML document, although the present inventioncould convert an object instance to a document having a serial formatother than XML, such as a custom binary format. Moreover, once themapping has been defined, an XML document can be converted to an objectinstance based on the mapping.

XML schema documents and source code can also be generated from themapping. The source code generated from the mapping describes only thedata portions of programming types and does not include any logic oralgorithmic statements.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and notlimitation in the accompanying figures in which like reference numeralsindicate similar elements and in which:

FIG. 1 shows a schematic diagram of a conventional general-purposedigital computing environment that can be used for implementing variousaspects of the present invention; and

FIG. 2 shows a data flow diagram for serializing an object instance to adocument having a serial format and for deserializing a document havinga serial format to an object instance according to the presentinvention.

DETAILED DESCRIPTION

The present invention may be more readily described with reference toFIGS. 1 and 2. FIG. 1 illustrates a schematic diagram of a conventionalgeneral-purpose digital computing environment that can be used toimplement various aspects of the present invention. In FIG. 1, acomputer 100 includes a processing unit 110, a system memory 120, and asystem bus 130 that couples various system components including thesystem memory to processing unit 110. System bus 130 may be any ofseveral types of bus structures including a memory bus or memorycontroller, a peripheral bus, and a local bus using any of a variety ofbus architectures. System memory 120 includes read only memory (ROM) 140and random access memory (RAM) 150.

A basic input/output system 160 (BIOS), containing the basic routinesthat help to transfer information between elements within computer 100,such as during start-up, is stored in ROM 140. The computer 100 alsoincludes a hard disk drive 170 for reading from and writing to a harddisk (not shown), a magnetic disk drive 180 for reading from or writingto a removable magnetic disk 190, and an optical disk drive 191 forreading from or writing to a removable optical disk 192 such as a CD ROMor other optical media. Hard disk drive 170, magnetic disk drive 180,and optical disk drive 191 are connected to the system bus 130 by a harddisk drive interface 192, a magnetic disk drive interface 193, and anoptical disk drive interface 194, respectively. The drives and theirassociated computer-readable media provide nonvolatile storage ofcomputer readable instructions, data structures, program modules andother data for personal computer 100. It will be appreciated by thoseskilled in the art that other types of computer readable media that canstore data that is accessible by a computer, such as magnetic cassettes,flash memory cards, digital video disks, Bernoulli cartridges, randomaccess memories (RAMs), read only memories (ROMs), and the like, mayalso be used in the example operating environment.

A number of program modules can be stored on hard disk drive 170,magnetic disk 190, optical disk 192, ROM 140 or RAM 150, including anoperating system 195, one or more application programs 196, otherprogram modules 197, and program data 198. A user can enter commands andinformation into computer 100 through input devices such as a keyboard101 and pointing device 102. Other input devices (not shown) may includea microphone, joystick, game pad, satellite dish, scanner or the like.These and other input devices are often connected to processing unit 110through a serial port interface 106 that is coupled to the system bus,but may be connected by other interfaces, such as a parallel port, gameport or a universal serial bus (USB). Further still, these devices maybe coupled directly to system bus 130 via an appropriate interface (notshown). A monitor 107 or other type of display device is also connectedto system bus 130 via an interface, such as a video adapter 108. Inaddition to the monitor, personal computers typically include otherperipheral output devices (not shown), such as speakers and printers.

Computer 100 can operate in a networked environment using logicalconnections to one or more remote computers, such as a remote computer109. Remote computer 109 can be a server, a router, a network PC, a peerdevice or other common network node, and typically includes many or allof the elements described above relative to computer 100, although onlya memory storage device 111 has been illustrated in FIG. 1. The logicalconnections depicted in FIG. 1 include a local area network (LAN) 112and a wide area network (WAN) 113. Such networking environments arecommonplace in offices, enterprise-wide computer networks, intranets andthe Internet.

When used in a LAN networking environment, computer 100 is connected tolocal area network 112 through a network interface or adapter 114. Whenused in a WAN networking environment, personal computer 100 typicallyincludes a modem 115 or other device for establishing a communicationsover wide area network 113, such as the Internet. Modem 115, which maybe internal or external, is connected to system bus 130 via the serialport interface 106. In a networked environment, program modules depictedrelative to personal computer 100, or portions thereof, may be stored ina remote memory storage device.

It will be appreciated that the network connections shown are exemplaryand other techniques for establishing a communications link between thecomputers can be used. The existence of any of various well-knownprotocols such as TCP/IP, Ethernet, FTP, HTTP and the like is presumed,and the system can be operated in a client-server configuration topermit a user to retrieve web pages from a web-based server. Any ofvarious conventional web browsers can be used to display and manipulatedata on web pages.

A primary aspect of the invention provides that when a schema for adocument having a serial format is known, the public properties, publicfields and method parameters of an object can be converted to a documenthaving the serial format for storage or for transport. Accordingly,deserialization of a document having a serial format recreates anobject-in its original state as long as the public properties and publicfields of the object comprise the entire state of the object.Preferably, the present invention serializes an instance of an object toan XML document, and deserializes an XML document to an instance of anobject.

FIG. 2 shows a data flow diagram for serializing an object instance 201to produce a document 202 having a serial format. According to theinvention, a mapping 203 between programming language constructscontained in annotated source code 204 and an XML schema 205 (andvice-versa) is used for flowing data between an object instance 201 andan XML document 202. Similarly, mapping 203 is used for flowing databetween an XML document 202 and an object instance 201. While thepresent invention will be described in the context of serializing anobject instance to an XML document and deserializing an XML document toan object instance, the concepts of the present invention can be appliedto serializing an object instance to a document having a serial format,such as a binary format, and deserializing a document having the serialformat to an object instance.

A schema contains information about how the XML should look, or bearranged, when data is serialized. A programming type (a class) containsinformation about how the object should look, or be arranged, whendeserialized. Thus, a class annotated with attributes containsinformation about what the object instance will look like and about howthe data should be serialized into XML. Through custom attributes, thesetwo sets of information are merged into mapping 203. It should be noted,though, that a complete mapping cannot be made solely by importing(i.e., analyzing) a schema because a schema does not contain completeinformation about what programming types should be created whenserializing. Only the annotated source code has both sets ofinformation. Nevertheless, it is possible to generate a mapping for theappropriate programming types using a set of predefined rules thatprimarily concern naming and that relate the schema to selectedprogramming types when generating source code from a schema. Typesgenerated from schema will have “default” names, that is, names that areusually the same names used in the schema. Another exemplary rulerelates to how arrays are represented. For example, an array in code canbe represented by using a conventional array or by using a collection.Each representation could be serialized in the same way in XML.

An XmlSerializer 206 and related tools, such as an XML Schema Definition(xsd.exe) tool, provide a bridge between programming languageconstructs/XSD schema (i.e., annotated code 204/XML schema 205) and anobject instance/XML document (i.e., object instance 201/XML document202) at both design time and run time. The XmlSerializer 206 isgenerated on demand the first time it is necessary to serialize ordeserialize an object instance of a given type.

When the design starting point is a given schema 205 that follows theXML Schema Definition (XSD) language that is proposed by the W3C, theXML Schema Definition (xsd.exe) tool is used for importing schema 205and for exporting source code 204 based on schema 205. When the designstarting point is annotated source code 204, annotated source code 204is compiled at 207 to produce compiled source code 208. That is, thedata in an object is described using programming language constructssuch classes, fields, properties, primitive types, or arrays. Customizedclasses, annotated with attributes, can be also be created by thepresent invention. A mapping 203 is generated by reflection at 209 basedon compiled annotated code 208.

Reflection is a facility provided by some programming systems, such asthe Common Language Runtime (CLR) provided by Microsoft of Redmond,Wash. in the .NET Framework, for code to inspect the nature of types(classes) available on the system. For example, a programmer can writecode that queries the system for a list of methods defined on a giventype. The information returned would include the names of the methods,their return types, and the names and types of parameters to themethods. Reflection can also be used to determine what properties andfields exist on a type, or what types have been defined on a system.

The Common Language Runtime provided by Microsoft for the NETenvironment allows code to be annotated with “custom attributes,” alsocalled “metadata.” The annotations are expressed by a programmer insource code. When compiled, the annotations are stored as additionalinformation about the classes, methods, fields, properties andparameters defined in the source code. The Runtime may then use theadditional information natively, or programs can use reflection toobtain the information.

Returning to FIG. 2, an XSD schema document (.xsd) is exported byxsd.exe from mapping 203 based on the custom classes of compiledannotated code 208. Thus, an XSD schema is optional and is not needed atdesign time (or at run time) because the present invention can generatea suitable schema based on annotated source code.

In either design situation, i.e., starting with a given schema orstarting with annotated source code, the classes are annotated withcustom attributes that are used by an XmlSerializer 206 for mappingbetween a XSD schema system to a Common Language Runtime (CLR)environment. The CLR environment is a runtime environment and is part ofthe NET framework provided by Microsoft of Redmond, Wash. The CLRprovides such features as cross-language integration and cross-languageexception handling among other features, for developing and executingNET applications.

At run time, instances of classes contained within an object instance201 are serialized by XmlSerializer 206 into an XML document 202 basedon mapping 203. Similarly, an XML document 202 is deserialized byXmlSerializer 206 into a run time object instance 201 based on mapping203. In this regard, XmlSerializer 206 provides complete and flexiblecontrol over how XML is encoded into classes. For example, a publicfield or public property can be encoded as an attribute or an element.An XML namespace can be specified, and an element name or attribute namecan be specified when a field or property name is inappropriate. Onlythe shape of an object class and the data contained in the object iscontained in the serialized data. The type identity and assemblyinformation is not included in the serialized data because only publicproperties and public fields are serialized by XmlSerializer 206. Insituations when non-public, i.e., private, data is to be serialized, aconventional binary formatting method is preferred.

The present invention provides the advantages of working withstrongly-typed classes while still having the flexibility of XML. Forexample, by using fields or properties of type XmlElement, XmlAttributeor XmlNode in strongly typed classes, parts of the XML document instancecan be read directly into XML objects. Attributes for the applicationprogramming interface (API) for XmlSerializer 206 for controlling XMLoutput and XML input are set forth in the following table: AttributeName Use SoapElementAttribute Allows specification of a field orproperty that should be serialized as an element in the XML document.Allows specification of the name and namespace for that element. Appliesto SOAP- encoded XML. SoapEnumAttribute Specifies the name to be used inXML Schema for the annotated enumeration. Applies to SOAP-encoded XML.SoapIgnoreAttribute Specifies that the annotated public field, property,or parameter should be ignored by the serializer and should not berepresented in the schema or serial document. Applies to SOAP-encodedXML. SoapIncludeAttribute Specifies an additional type to be included inthe reflection process. All types encountered when examining fields,properties, and parameters are included automatically.SoapIncludeAttribute can be used when subclasses not declared asproperty types will be used. Applies to SOAP-encoded XML.SoapTypeAttribute Allows the type definition emitted in the schemadocument to be customized. Applies to SOAP-encoded XML.XmlAnyAttributeAttribute When deserializing, the array will be filledwith XmlElement objects that represent all XML elements unknown to theschema. Applies to “literal” (XSD- based) XML. XmlAnyElementAttributeWhen deserialzing, the array will be filled with XmlAttribute objectsthat represent all XML attributes unknown to the schema. Applies to“literal” (XSD- based) XML. XmlArrayAttribute The members of an arraywill be generated as members of an XML array. Applies to “literal”(XSD-based) XML. XmlArrayItemAttribute Derived types that can beinserted into an array. Applies to “literal” (XSD-based) XML.XmlAttributeAttribute The class will be serialized as an XML attribute.Applies to “literal” (XSD-based) XML. XmlElementAttribute The field orproperty will be serialized as an XML element. Applies to “literal”(XSD-based) XML. XmlEnumAttribute The element name of an enumerationmember. Applies to “literal” (XSD- based) XML. XmlIgnoreAttribute Theproperty or field should be ignored when the containing class isserialized. Applies to “literal” (XSD-based) XML. XmlIncludeAttributeThe class should be included when generating schemas (and will thus berecognized when serialized). Applies to “literal” (XSD-based) XML.XmlRootAttribute The class represents the root element of the XMLdocument. (Use the attribute to further specify the namespace andelement name. Applies to “literal” (XSD-based) XML. XmlTextAttributeThat the property or field should be serialized as XML. Applies to“literal” (XSD-based) XML. XmlTypeAttribute That the class should beserialized as an XML type. Applies to “literal” (XSD- based) XML.

The XmlAnyElementAttribute or XmlAnyAttributeAttribute attributes can beapplied to fields or properties that return arrays of XmlElement,XmlAttribute or XmlNode objects for reading unmapped elements andattributes into these fields or properties. Thus, documents can beprocessed that have additional elements and attributes that were addedafter design time and that were not known when the strongly-typedclasses were designed.

When a property or field returns a complex object (such as an array or aclass instance), XmlSerializer 206 converts the complex object to anelement nested within the main XML document. For example, the firstclass in the following exemplary C# code returns an instance of thesecond class: public Class MyContainer { public MyObjectMyObjectProperty; } public class MyObject { public string ObjectName; }

The serialized XML output provided by XmlSerializer 206, given aninstance of the classes MyContainer and MyObject, will be: <MyContainer><MyObjectProperty> <ObjectName>My String</ObjectName></MyObjectProperty> </MyContainer>

For this example, “My String” is a particular value the class ObjectNamein the given instance of the classes MyContainer and MyObject.

When only the states of objects are saved, the class does not need to bemodified. When, however, XML documents that conform to an exact XMLschema are to be read or written, the XML output of XmlSerializer 206can be controlled by setting selected attributes of the publicproperties and fields of the class. As shown in the following exemplaryC# code, XmlAttributeAttribute is used for specifying that the Qty fieldshould be encoded as an XML attribute having the name Quantity.Additionally, XmlElementAttribute is used for specifying that the Namefield should be encoded as an XML element having the name ProductName.public class Order { [XmlAttribute (AttributeName = “Quantity”)] publicint Qty; [XmlElement (ElementName = “ProductName”)] public string Name;}

After serialization by XmlSerializer 206, the XML code appears as:<Order Quantity = ‘15’> <ProductName>.NET</ProductName> </Order>

When XmlSerializer 206 deserializes an instance of the class Order, theElementName and AttributeName properties describe how to treat theproperties named Qty and Name so that XmlSerializer 206 accuratelyreconstructs the object with the correct field and property values.

The following exemplary code also illustrates that each public field orpublic property of an object can be controlled by attributes: usingSystem; using System.Xml; using System.Xml.Serialization; usingSystem.IO; /* The XmlRootAttribute allows you to set an alternate name(PurchaseOrder)of the XML element, the element namespace; by default,the XmlSerializer uses the class name. The attribute also allows you toset the XML namespace for the element. Lastly, the attribute sets theIsNullable property, which species whether the xsi:null attributeappears if the class instance is sset to a null reference. */[XmlRootAttribute(“PurchaseOrder”, Namespace=“http://www.cpandl.com”,IsNullable = false)] public class PurchaseOrder { public Address ShipTo;public string OrderDate; /* The XmlArrayAttribute changes the XMLelement name from the default of “OrderedItems” to “Items”. */[XmlArrayAttribute(“Items”)] public OrderedItem[] OrderedItems; publicdecimal SubTotal; public decimal ShipCost; public decimal TotalCost; }public class Address { /* The XmlAttribute instructs the XmlSerializerto serialize the Name field as an XML attribute instead of an XMLelement (the default behavior). */ [XmlAttribute] public string Name;public string Line1; /* Setting the IsNullable property to falseinstructs the XmlSerializer that the XML element will not appear if theCity field is set to a null reference. */[XmlElementAttribute(IsNullable = false)] public string City; publicstring State; public string Zip; } public class OrderedItem { publicstring ItemName; public string Description; public decimal UnitPrice;public int Quantity; public decimal LineTotal; /* Calculate is a custommethod that calculates the price per item, and stores the value in afield. */ public void Calculate( ) { LineTotal = UnitPrice * Quantity; }} public class Test { public static void Main( ) { string filename =“po.xml”; // Create an instance of the XmlSerializer class; // specifythe type of object to serialize. XmlSerializer serializer = newXmlSerializer(typeof(PurchaseOrder)); TextWriter writer = new StreamWriter(filename); PurchaseOrder po=new PurchaseOrder( ); // Create anaddress to ship and bill to. Address billAddress = new Address( );billAddress.Name = “Rita Hernandez”; billAddress.Line1 = “1 Main St.”;billAddress.City = “AnyTown”; billAddress.State = “WA”; billAddress.Zip= “00000”; // Set ShipTo and BillTo to the same addressee. po.ShipTo =billAddress; po.OrderDate = System.DateTime.Now.ToLongDateString( ); //Create an OrderedItem object. OrderedItem i1 = new OrderedItem( );i1.ItemName = “Widget S”; i1.Description = “Small widget”; i1.UnitPrice= (decimal) 5.23; i1.Quantity = 3; i1.Calculate( ); // Insert the iteminto the array. OrderedItem [ ] items = {i1}; po.OrderedItems = items;// Calculate the total cost. decimal subTotal = new decimal( );foreach(OrderedItem oi in items) { subTotal += oi.LineTotal; }po.SubTotal = subTotal; po.ShipCost = (decimal) 12.51; po.TotalCost =po.SubTotal + po.ShipCost; // Serialize the purchase order, and closethe TextWriter. serializer.Serialize(writer, po); writer.Close( ); } }

creates the following XML (in the file referred to as po.xml): <?xmlversion=“1.0” encoding=“utf-8”?> <PurchaseOrderxmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”xmlns=“http://www.cpandl.com”> <ShipTo Name=“Rita Hernandez”> <Line1>1Main St.</Line1> <City>AnyTown</City> <State>WA</State> <Zip>00000</Zip></ShipTo> <OrderDate>Tuesday, June 26, 2001</OrderDate> <Items><OrderedItem> <ItemName>Widget S</ItemName> <Description>Smallwidget</Description> <UnitPrice>5.23</UnitPrice> <Quantity>3</Quantity><LineTotal>15.69</LineTotal> </OrderedItem> </Items><SubTotal>15.69</SubTotal> <ShipCost>12.51</ShipCost><TotalCost>28.2</TotalCost> </PurchaseOrder>

Notice the following general features of source code annotation:

-   -   Classes, properties, fields, methods, parameters, and other        language elements can be annotated with “custom attributes.”    -   In the C# language, the syntax for annotating these language        elements is to place the name of a custom attribute inside        square brackets just before the item being annotated. Additional        data is provided to the custom attribute inside parentheses        following the attribute name.

System.XmlSerialization.XmlSerializer is the main class used for XMLSerialization. The previous example illustrates how to useSystem.XmlSerialization.XmlSerializer for serializing an object instanceto XML by calling the Serialize method. Similarly, an object can bedeserialized using the Deserialize method, which takes a stream fromwhich to read the XML document and returns the deserialized object.

An exemplary use of the XML Definition Tool (Xsd.exe) could be that of adeveloper tasked with developing an application for processing XMLdocuments that must conform to a specific XML schema (.xsd) document,such as a particular purchase order. Orders that conform to the XMLschema are processed and a confirmation reply is sent to each customer.The specific XML schema is passed to the XML Schema Definition tool(Xsd.exe) as an argument, and the XML Schema Definition tool creates aset of classes that are precisely matched to the specified XML schema.According to the invention, the XML Schema Definition tool processesonly schemas that conform to the www.w3.org Proposed RecommendationXMLSchema specification set forth at http://www.w3.org/2001/XMLSchema.The classes having methods, properties, or fields are annotated, asrequired, by the reflection portion of the invention (i.e., reflection209 in FIG. 2) for the specific XML schema.

Xsd.exe will produce the following schema for the classes used in theprevious example: <?xml version=“1.0” encoding=“utf-8”?> <xs:schemaxmlns:tns=“http://www.cpandl.com” attributeFormDefault=“qualified”elementFormDefault=“qualified” targetNamespace=“http://www.cpandl.com”xmlns:xs=“http://www.w3.org/2001/XMLSchema”> <xs:elementname=“PurchaseOrder” type=“tns:PurchaseOrder” /> <xs:complexTypename=“PurchaseOrder”> <xs:sequence> <xs:element minOccurs=“0”maxOccurs=“1” name=“ShipTo” type=“tns:Address” /> <xs:elementminOccurs=“0” maxOccurs=“1” name=“OrderDate” type=“xs:string” /><xs:element minOccurs=“0” maxOccurs=“1” name=“Items”type=“tns:ArrayOfOrderedItem” /> <xs:element minOccurs=“1” maxOccurs=“1”name=“SubTotal” type=“xs:decimal” /> <xs:element minOccurs=“1”maxOccurs=“1” name=“ShipCost” type=“xs:decimal” /> <xs:elementminOccurs=“1” maxOccurs=“1” name=“TotalCost” type=“xs:decimal” /></xs:sequence> </xs:complexType> <xs:complexType name=“Address”><xs:sequence> <xs:element minOccurs=“0” maxOccurs=“1” name=“Line1”type=“xs:string” /> <xs:element minOccurs=“0” maxOccurs=“1” name=“City”type=“xs:string ”/> <xs:element minOccurs=“0” maxOccurs=“1” name=“State”type=“xs:string” /> <xs:element minOccurs=“0” maxOccurs=“1” name=“Zip”type=“xs:string” /> </xs:sequence> <xs:attribute name=“Name”type=“xs:string” /> </xs:complexType> <xs:complexTypename=“ArrayOfOrderedItem”> <xs:sequence> <xs:element minOccurs=“0”maxOccurs=“unbounded” name=“OrderedItem” type=“tns:OrderedItem” /></xs:sequence> </xs:complexType> <xs:complexType name=“OrderedItem”><xs:sequence> <xs:element minOccurs=“0” maxOccurs=“1” name=“ItemName”type=“xs:string” /> <xs:element minOccurs=“0” maxOccurs=“1”name=“Description” type=“xs:string” /> <xs:element minOccurs=“1”maxOccurs=“1” name=“UnitPrice” type=“xs:decimal” /> <xs:elementminOccurs=“1” maxOccurs=“1” name=“Quantity” type=“xs:int” /> <xs:elementminOccurs=“1” maxOccurs=“1” name=“LineTotal” type=“xs:decimal” /></xs:sequence> </xs:complexType> </xs:schema>

Similarly, running xsd.exe on that schema would produce classes thatlook substantially like the classes originally written for the example.

The application for processing the XML documents conforming to aspecific XML purchase order schema is then created using XmlSerializer206 for reading and processing XML documents, and for generating new XMLdocuments confirming orders. To do this, XmlSerializer 206 serializesand deserializes the classes created by the XML Schema Definition tool.

Xml Serialization can serialize the parameters of a method in much thesame way that a class is serialized. For example, Xml Serialization ofattributes for Web Services also allows flexible sets of Web Services tobe created and easily shape the Simple Object Access Protocol (SOAP)that a Web Service expects and responds with. There are two sets of XmlSerialization attributes for Web Services: one attribute set forservices described literally by an XSD document, and another attributeset for services that use the SOAP encoding, as defined in Section 5 ofthe SOAP spec, http://www.w3.org/TR/SOAP/.

For literal services, the attributes listed above can be used forcontrolling the shape, or arrangement, of the XML document that is beingsent to a web service. For example, the following C# code: <%@WebServicelanguage=“c#” class=“SimpleTest”%> using System; using System.Xml; usingSystem.Xml.Serialization; using System.Web.Services; usingSystem.Web.Services.Protocols; public class SimpleTest { [WebMethod][SoapDocumentMethod(ParameterStyle=SoapParameterStyle.Bare)] public DataSendData(Data x) { return x; } } public class Data {[XmlElement(“TheInt”)] public int MyInt; [XmlAttribute(“str”)] publicstring MyString; }

Creates the Following Xml for SOAP: Request: POST /test.asmx HTTP/1.1Host: localhost Content-Type: text/xml; charset=utf-8 Content-Length:length SOAPAction: “http://tempuri.org/SendData” <?xml version=“1.0”encoding=“utf-8”?> <soap:Envelopexmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”xmlns:soap=“http://schemas.xmlsoap.org/soap/envelope/”> <soap:Body> <xstr=“string” xmlns=“http://tempuri.org/”> <TheInt>int</TheInt> </x></soap:Body> </soap:Envelope> Response: HTTP/1.1 200 OK Content-Type:text/xml; charset=utf-8 Content-Length: length <?xml version=“1.0”encoding=“utf-8”?> <soap:Envelopexmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”xmlns:soap=“http://schemas.xmlsoap.org/soap/envelope/”> <soap:Body><SendDataResult str=“string” xmlns=“http://tempuri.org/”><TheInt>int</TheInt> </SendDataResult> </soap:Body> </soap:Envelope>

For encoded SOAP, the Soap* Attributes found withinSystem.Xml.Serialization can be used for controlling the shape of theXML. For instance, the following C# code: <%@WebService language=“c#”class=“SimpleTest”%> using System; using System.Xml; usingSystem.Xml.Serialization; using System.Web.Services; usingSystem.Web.Services.Protocols; public class SimpleTest { [WebMethod][SoapRpcMethod] public Data SendData(Data x) { return x; } } publicclass Data { [XmlElement(“TheInt”)] public int MyInt;[XmlAttribute(“str”)] public string MyString; }

Creates the Following SOAP: Request: POST /test.asmx HTTP/1.1 Host:localhost Content-Type: text/xml; charset=utf-8 Content-Length: lengthSOAPAction: “http://tempuri.org/SendData” <?xml version=“1.0”encoding=“utf-8”?> <soap:Envelopexmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”xmlns:soapenc=“http://schemas.xmlsoap.org/soap/encoding/”xmlns:tns=“http://tempuri.org/”xmlns:types=“http://tempuri.org/encodedTypes”xmlns:soap=“http://schemas.xmlsoap.org/soap/envelope/”> <soap:Bodysoap:encodingStyle=“http://schemas.xmlsoap.org/soap/encoding/”><tns:SendData> <x href=“#id1” /> </tns:SendData> <types:Data id=“id1”xsi:type=“types:Data”> <MyInt xsi:type=“xsd:int”>int</MyInt> <MyStringxsi:type=“xsd:string”>string</MyString> </types:Data> </soap:Body></soap:Envelope> Response: HTTP/1.1 200 OK Content-Type: text/xml;charset=utf-8 Content-Length: length <?xml version=“1.0”encoding=“utf-8”?> <soap:Envelopexmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”xmlns:soapenc=“http://schemas.xmlsoap.org/soap/encoding/”xmlns:tns=“http://tempuri.org/”xmlns:types=“http://tempuri.org/encodedTypes”xmlns:soap=“http://schemas.xmlsoap.org/soap/envelope/”> <soap:Bodysoap:encodingStyle=“http://schemas.xmlsoap.org/soap/encoding/”><tns:SendDataResponse> <SendDataResult href=“#id1” /></tns:SendDataResponse> <types:Data id=“id1” xsi:type=“types:Data”><MyInt xsi:type=“xsd:int”>int</MyInt> <MyStringxsi:type=“xsd:string”>string</MyString> </types:Data> </soap:Body></soap:Envelope>

While the invention has been described with respect to specific examplesincluding presently preferred modes of carrying out the invention, thoseskilled in the art will appreciate that there are numerous variationsand permutations of the above described systems and techniques that fallwithin the spirit and scope of the invention as set forth in theappended claims.

1. A computer-readable medium having stored thereon a data structure, comprising: a first data field containing data representing a class; and a second data field containing data representing an attribute of the class, the attribute indicating that an instance of the class is to be serialized to XML formatted data.
 2. A computer-readable medium according to claim 1, wherein the attribute specifies an XML namespace.
 3. A computer-readable medium according to claim 1, wherein the attribute specifies an XML namespace named XmlRootAttribute.
 4. A computer-readable medium according to claim 1, wherein the attribute specifies an XML element name.
 5. A computer-readable medium according to claim 1, wherein the attribute specifies an XML element named XmlRootAttribute.
 6. A computer-readable medium having stored thereon a data structure, comprising: a first data field containing data representing a class; a second data field containing data representing a member of the class that produces a return value; and a third data field containing data representing an attribute, the attribute indicating that the return value is to be serialized to XML formatted data.
 7. A computer-readable medium according to claim 6, wherein the attribute specifies an XML element name.
 8. A computer-readable medium according to claim 6, wherein the attribute specifies an XML element named XmlElementAttribute.
 9. A computer-readable medium according to claim 6, wherein the attribute specifies an XML attribute name.
 10. A computer-readable medium according to claim 6, wherein the attribute specifies an XML attribute named XmlAttributeAttribute.
 11. A computer-readable medium according to claim 6, wherein the attribute specifies that the return value is to be serialized into an XML array.
 12. A computer-readable medium according to claim 6, wherein the attribute is named XmlArrayAttribute and specifies that the return value is to be serialized into an XML array.
 13. A computer-readable medium according to claim 6, wherein the member of the class is a method.
 14. A computer-readable medium according to claim 6, wherein the member of the class is a property.
 15. A computer-readable medium having stored thereon a data structure, comprising: a first data field containing data representing a class; a second data field containing data representing a member of the class; a third data field containing data representing an attribute, the attribute indicating that the member off the class is to be serialized to XML formatted data.
 16. A computer-readable medium according to claim 15, wherein the member of the class is one of a method, a property, or an enum.
 17. A computer-readable medium according to claim 15, wherein the member of the class is an enum and the attribute is named XmlEnumAttribute.
 18. A computer-readable medium according to claim 15, wherein the member of the class is a method.
 19. A computer-readable medium according to claim 15, wherein the member of the class is a method and the attribute is named XmlIncludeAttribute.
 20. A computer-readable medium having stored thereon a data structure, comprising: a first data field containing data representing a class; a second data field containing data representing a member of the class, the property returning a value; and a third data field containing data representing an attribute, the attribute indicating that the value is not to be serialized to XML formatted data.
 21. A computer-readable medium according to claim 20, wherein the attribute is named XmlIgnoreAttribute.
 22. A computer-readable medium according to claim 20, wherein the member of the class is one of a method, a property, or an enum. 